The lines I am referring to are parts 4 and 5. The are connected to the heat exchanger, which cools the fluid.

Alex,

I thought about that, but I was skeptical about draining the fluid from the pan, and then starting the car. Wouldn't that starve the fluid pump? I am not sure how exactly the fluid is pumped around in the trans. Is it a pump with vanes, or some other kind of vacuum suction system. Also, I was a little concerned that the fluid may flow too fast if I used the trans pump itself, didn't wanna make a mess.

Although I am doubtful if any hand operated pump would be able to create enough pressure to completely circulate through all the nooks and crannies of the valve body.

I also read up about the types of failures and recently ran into the ZF rebuild thread. It gave me a lot of relief to see that.